Simulating a Mobile Network with Shared Access Channels

ABSTRACT

A method for simulating a mobile telephone network with shared-access channels. The simulation method includes the steps of simulating at least a first and a second configuration of the mobile telephone network that are statistically independent one from the other. Each one of the steps of simulating includes at least the steps of: determining a number of mobile terminals generating a packet data traffic; assigning to a list of mobile terminals included in the number of mobile terminals generating a packet data traffic, at least one shared-access channel of the mobile telephone network to be simulated; and performing a scheduling management algorithm of the list of mobile terminals on the shared-access channel.

The present invention refers in general to the field of mobiletelephones and in particular to a mobile telephone network. More inparticular, the present invention refers to a method and a system forsimulating the behaviour of a mobile telephone network, that can provideservices through shared-access channels, based for example on theGSM/GPRS (Global System for Mobile Communications/General Packet RadioService) standard or on the EDGE (Enhanced Data for GSM Evolution)standard or on the HSDPA (High-Speed Downlink Packet Access) standard oron the UMTS (Universal Mobile Telecommunication System) standard.

Planning of a network requires the designers to evaluate performances ofa network based on geographic data, on network configurations and onexpected service requests. The tools that simulate the operation of anetwork provide a practical method for planning the network itself. Thenetwork planning tools allow the designers to simulate the operation ofvarious network configurations by performing modifications on thenetwork based on statistical data obtained as simulation output.

Currently-available cellular network planning tools are generally basedon simulators of the static type or of the dynamic type.

In static simulations, the time variable is not taken into account, butthe network is analysed in a particular state, as if it were analysedthrough a photograph. By carrying out many network analyses (many“photographs” called “snapshots”) in different states, it is possible toobtain a global network evaluation.

A static simulation of a GSM network is described, for example, in T. M.Gill “A simulation of a GSM network with frequency hopping”, 1991 SixthInternational Conference on Mobile Radio and Personal Communications(Conf. Pul. No. 351) p. 167-74.

In dynamic simulations, the time variable is instead taken into accountand the subsequent changes of the network state are regulated by“events”; each “event” represents the realisation of a condition thatdetermines the change of the network state. By carrying out a simulationthat takes into account the network state evolution for a certain timelength, it is possible to obtain a global network evaluation.

In WO 02/104055, in the name of the Applicant itself, a dynamicsimulation system is for example disclosed, characterised by a modularstructure based on interchangeable objects that are able to beselectively activated, which comprises a simulation engine and aplurality of modules representative of apparatuses and elements of thenetwork to be simulated. Due to such structure, the system allowssimulating highly complex networks.

Dynamic simulators are also used for simulating the mobile telephonenetworks with shared-access channels (such as for example the GPRSnetwork). The shared-access channels are physical channels, generallyused for packet data transmission, which can be shared among many users.For example, the shared-access channels can be used when the packet datatransmission is of the intermittent type (such as the download of a Webpage) or when a mobile terminal uses a service of the Best-Effort type,namely a service for which the mobile telephone operator cannotguarantee a high quality level. Suitable algorithms, so-calledscheduling algorithms, which are part of the set ofprocedures/algorithms for managing radio resources (Radio ResourceManagement or RRM) in a mobile telephone network, schedule, in time, thesharing of a single physical channel among different users.

Dynamic simulators, taking into account the time variable, are able tosimulate the behaviour of the mobile telephone networks withshared-access channels. In particular, the use of dynamic simulatorsallows evaluating the effect/impact of scheduling algorithms onperformances of this type of networks.

The Applicant has however observed that the use of dynamic simulatorsimplies rather high simulation times if compared with simulation timesobtained by using static simulators, above all when networks to besimulated are big-sized and with high complexity.

The Applicant therefore posed itself the problem of making a staticsimulator that is able to simulate a mobile telephone network withshared-access channels with adequate accuracy and reliability, thoughwithout taking into account the time variable.

The invention solves the above-stated technical problem by introducing,in a static simulator, a module that is able to simulate the managementof user scheduling on the shared-access channels of the mobile telephonenetwork to be simulated.

According to the present invention, during each analysis (“photograph orsnapshot”) of the mobile telephone network to be simulated, the modulethat manages the user scheduling in turn enables all (or a substantialportion of) the users, that generate a packet data traffic, totransmit/receive on at least one of the shared-access channels beingpresent in the network itself. At the end of the simulation, the meanthroughput can be calculated, namely the mean of informationtransferred, per time unit, from each mobile terminal onto theshared-access channels on which it has been enabled to transmit/receiveduring the simulation.

The Applicant has observed that the above-stated problem can be solvedby a method for simulating a mobile telephone network with shared-accesschannels comprising at least the steps of:

-   -   simulating a first configuration of said mobile telephone        network;    -   simulating a second configuration of said mobile telephone        network;    -   said first and second configuration of said mobile telephone        network being statistically independent one from the other;        each one of said steps of simulating comprising at least the        steps of:    -   determining a number of mobile terminals generating a packet        data traffic;    -   assigning to a list of mobile terminals, included in said number        of mobile terminals generating a packet data traffic, at least        one shared-access channel of said mobile telephone network to be        simulated; and    -   executing a scheduling management algorithm of said list of        mobile terminals on said shared-access channel.

Another aspect of the present invention refers to a system forsimulating at least a first and a second configuration of a mobiletelephone network, said first and second configuration of said mobiletelephone network being statistically independent one from the other andeach comprising a number of mobile terminals to be simulated generatinga packet data traffic, said simulating system including:

-   -   at least one object representing a network controller belonging        to said mobile telephone network; said at least one object        comprising modules configured for:    -   assigning to a list of mobile terminals, included in said number        of mobile terminals generating a packet data traffic, at least        one shared-access channel of said mobile telephone network to be        simulated; and    -   executing a scheduling management algorithm of said list of        mobile terminals on said shared-access channel.

A further aspect of the present invention refers to a computer programproduct that can be loaded in the memory of at least one electronicprocessor and comprising portions of software code for performing theprocess according to the invention when the product is executed on aprocessor: in this context such statement must be deemed whollyequivalent to the mention of means that can be read by a computercomprising instructions for checking a network of computers in order toperform a process according to the invention. The reference to “at leastone electronic processor” is obviously aimed to enlighten the chance ofperforming the arrangement according to the invention in ade-centralised context.

Further preferred aspects of the present invention are described in thedependent claims and in the present description.

The characteristics and the advantages of the present invention willappear from the herein below description of an embodiment thereof,provided merely as a non-limiting example, with reference to theenclosed drawings, in which:

FIG. 1 shows a client-server architecture through which the simulationmethod according to the invention operates;

FIG. 2 shows an exemplified structure of a simulator made according tothe invention;

FIG. 3 shows simulation objects used by the simulator in FIG. 2; and

FIGS. 4 and 5 show flow diagrams related to the simulation methodaccording to the invention.

With reference to FIG. 1, the method for simulating a mobile telephonenetwork, providing services through shared-access channels according tothe invention, can operate through a client-server architecture 1, of aknown type, described below. As a non-limiting example, the mobiletelephone network which will be referred to in the following descriptionis a mobile telephone network of the GSM/GPRS type (herein below called“GSM/GPRS network”). However the simulation method according to theinvention can be applied also to mobile telephone networks based forexample on the EDGE or HSDPA or UMTS standards.

Moreover, the following description will define as GSM mobile terminalsall mobile terminals that are able to generate a voice-type traffic andas GPRS mobile terminals all mobile terminals that are able to generatea packet data traffic. In particular, the packet data traffic generatedby the GPRS mobile terminals can be, for example:

a continuous traffic from/to the GPRS mobile terminal, for example afile transfer using a FTP (File Transfer Protocol) protocol;

a traffic of the WWW (World Wide Web) type, namely the downloading ofWeb pages as packets representing the various objects forming each Webpage.

Always with reference to FIG. 1, the client-server architecture 1comprises: a client processor 2, for example a Personal Computer, onwhich a graphic interface program 3, of a known type, is installed; aserver processor 4, for example a Work Station, on which a simulator 5,of the static type, is installed, for simulating the GSM/GPRS network.

Specifically, the simulator 5 receives as input:

a configuration file 6 comprising a set of network configurationparameters, listed in the following description, describing thecharacteristics of the GSM/GPRS network. Network configurationparameters are defined by the mobile telephone operator by using thegraphic interface program 3;

a structured set of territory data extracted from a territory data base7. This set of territory data can comprise data regarding: expectedtraffic, height, morphology, buildings on each territory element (pixel)forming the area in which the GSM/GPRS network will be planned;

and provides as output:

a set of statistical data, listed herein below in the description,describing the performance of the GSM/GPRS network. These statisticaldata are then stored, in a structured way, in a simulation data base 8and afterwards are sent to the graphic interface program 3 that displaysthem.

As shown in FIG. 1, client processor 2 and server processor 4 aremutually interconnected through a data network 9, of a known type, basedfor example on a protocol of the TCP/IP type. Alternatively, clientprocessor 2 and server processor 4 can be a single processor.

The network configuration parameters included in the configuration file6 can for example comprise:

the number of cells including in the GSM/GPRS network;

the geographic position of the cells themselves;

the number of transceiver stations (Base Transceiver Station or BTS)being present in the network;

the indication, for each transceiver station BTS, of the cellsassociated therewith;

the characteristics of each transceiver station BTS, such as forexample: antenna gain, radiation diagram; maximum radiation direction(defined in terms of azimuth and tilt); noise digit of receiversincluded in each transceiver station BTS; antenna connection losses;transmission powers associated with common channels;

characteristics of mobile terminals to be simulated, such as for examplenoise figure of the receiver included in each GSM/GPRS mobile terminal,gain and losses associated with the terminal antenna, maximumtransmission power available for the uplink connection (namely thecommunication occurring from mobile terminal to transceiver station),power dynamics of the mobile terminal; and

control parameters for radio resources managing procedures/algorithms,comprising, for example: number of radio resources that can be assignedto GSM mobile terminals and number of radio resources that can beassigned to GPRS mobile terminals.

Moreover, the statistical data obtained as output from the simulator 5and stored in the simulation data base 8 can, for example, comprise:

mean throughput for each GPRS mobile terminal, namely the mean ofinformation transferred per time unit from each GPRS mobile terminalonto the shared-access channels assigned thereto during the simulation;and

mean value of signal/noise ratio measured from each GPRS mobile terminalonto the shared-access channels assigned thereto during the simulation.

For each shared-access channel, the signal/noise ratio measured from theGPRS mobile terminal corresponds to the ratio between power associatedwith data packets that the mobile terminal is receiving on such channeland the remaining power received by the mobile terminal on the samechannel.

With reference to FIG. 2, the simulator 5, implemented for example inANSI C++ programming language by means of a project platform of the UML(“Unified Modelling Language”) type, comprises, according to a so-calledobject-oriented approach:

a simulation engine 10, providing for management and evolution of thesimulation; and

a plurality of objects, designated by reference number 12, each onerepresenting a physical device of the GSM/GPRS network, as betterdescribed in the following description.

According to the object-oriented approach, the elementary decompositionunit is not the operation (procedure), but the object, represented as anaggregation of variables, data structures and procedures which areconsidered a single entity by the simulator. In the examined case, thesimulation objects correspond, in general, to real entity models (realworld objects).

Moreover, it can be noted that, during the simulation, each simulationobject directly interacts with the remaining objects, by sendinginformation elements called “messages”. Specifically, the communicationthrough messages is characterised in that the reception of informationby the destination object occurs simultaneously with the transmission bythe source object.

With reference to FIG. 3, the plurality of objects 12 can comprise:

at least one object of the BSC_MC type, designated by reference number17, comprising at least three modules BSC_RRM_MC 20, BSC_RR_MC 21 andBSC-MAC_MC 22, shown in more detail in the following description,simulating the behaviour of a Network Controller (“Base StationController”). Within a mobile telephone network, the Network Controllersmanage radio resources and control the radio transport;

a plurality of objects of the BTS_MC type, each one designated byreference number 18, simulating the behaviour of transceiver stationsBTS of the GSM/GPRS network. Each object 18 of the BTS_MC type comprisesat least one module BTS_PHY_MC 23, shown in more detail in the followingdescription; and

a plurality of objects of the MS_MC type, each one designated byreference number 19, simulating the behaviour of the mobile terminals ofthe GSM/GPRS network. Each object of the MS_MC 19 type comprises atleast two modules MS_RR_MC 24 and MS_PHY_MC 25, shown in more detail inthe following description. In a preferred embodiment, each object 19 ofthe MS_MC type can be of the GSM type, namely it can simulate thebehaviour of a GSM mobile terminal or can be of the GPRS type, namely itcan simulate the behaviour of a GPRS mobile terminal.

More in detail:

module BSC_RRM_MC 20, included in object 17 of the BSC_MC type,simulates the assignment of radio resources for calls related to objects19 of the MS_MC type. In a preferred embodiment of the presentinvention, module BSC_RRM_MC 20 receives from module BSC_RR_MC 21 arequest message for assigning radio resources for each object 19 of theMS_MC type, processes such request and sends a message to moduleBSC_RR_MC 21 for assigning radio resources to each object 19 of theMS_MC type for which a request has been made;

module BSC_RR_MC 21, included in object 17 of the BSC_MC type, simulatesthe configuration of each one of modules BSC_MAC_MC 22, BTS_PHY_MC 23and MS_RR_MC 24, respectively included in object 17 of the BSC_MC typeand in each object 18 of the BST_MC type and each object 19 of the MS_MCtype, and activation/deactivation of calls related to objects 19 of theMS_MC type. According to a preferred embodiment of the presentinvention, module BSC_RR_MC 21 sends to each one of modules BSC_MAC_MC22, BTS_PHY_MC 23 and MS_RR_MC 24 a configuration message, so that thesemodules appropriately use radio resources assigned thereto by moduleBSC_RRM_MC 20. Moreover, module BSC_RR_MC 21 sends to each one ofmodules BSC_MAC_MC 22, BTS_PHY_MC 23 and MS_RR_MC 24 a messagecontaining indications about activation/deactivation of calls related toobjects 19 of the MS_MC type, for example indications dealing withbeginning and end of activation of calls;

module BSC_MAC_MC 22, included in object 17 of the BSC_MC type,according to the present invention, simulates the scheduling management(“scheduling algorithm”) of objects 19 of the MS_MC type, simulating thebehaviour of GPRS mobile terminals, on the shared-access channels of theGSM/GPRS network;

module BTS_PHY_MC 23, included in each object 18 of the BTS_MC type,simulates the physical level of the transceiver station BTS of theGSM/GPRS network and comprises a plurality of objects of the cell type,not shown in FIG. 2;

module MS_RR_MC 24, included in each object 19 of the MS_MC type,simulates the configuration of radio resources assigned to GSM and GPRSmobile terminals by module BSC_RRM_MC 20 and the management ofactivation/deactivation of calls for each of the above mobile terminals.As already previously illustrated, module MS_RR_MC 24 receives frommodule BSC_RR_MC 21 a configuration message for radio resources and amessage containing indications about activation/deactivation of calls.In turn, module MS_RR_MC 24 sends these messages to module MS_PHY_MC 25,included in each object 17 of the MS_MC type, in order to correctly setsuch module 8 (arrow 30 in FIG. 3); and

module MS_PHY_MC 25 simulates the physical level of GSM and GPRS mobileterminals.

The simulation method according to the invention will now be describedwith reference to FIG. 3 and to the flow diagram shown in FIG. 4. Indetail, the flow diagram in FIG. 4 shows a simulation algorithm 100 thatoperates according to the invention.

It can be stated that the evolution of the simulation algorithm 100depends on the simulation engine 10 that controls the sequence ofsimulation steps included in the algorithm itself.

In detail, the simulation algorithm 100 according to the invention cancomprise a step of initialisation of the simulation 110 and one or moreiterative steps of event-based micro-simulation 120.

In each event-based micro-simulation step 120, a network configurationis simulated (in terms of mobile terminals distribution), and allnetwork configurations simulated during the simulation are statisticallyindependent one from the other.

In the following description and claims, the term “statisticallyindependent” means that two network configurations simulated in twofollowing event-based micro-simulations are not the temporal evolutionone of the other.

In detail, the step of initialisation of the simulation 110 can comprisethe following steps performed by the simulation engine 10:

reading the parameters included in the configuration file 6;

creating the simulation objects depending on network configurationparameters read from the configuration file 6. More specifically, thesimulation engine 10 instantiates the objects 17 of the BSC_MC type, theobjects 18 of the BTS_MC type and the objects 19 of the MS_MC;

bi-directionally connecting the simulation objects, as indicated in theconfiguration file 6: in particular the bi-directional connection allowsa simulation object to be able to interact with another simulationobject and vice versa. More specifically, the simulation engine 10connects objects 17 of the BSC_MC type with objects 18 of the BTS_MCtype and objects 19 of the MS_MC type (arrows 31 and 32 in FIG. 3) andobjects 19 of the MS_MC type with objects 18 of the BTS_MC type (arrow33 in FIG. 3); and

initialising objects 17 of the BSC_MC type, objects 18 of the BTS_MCtype and objects 19 of the MS_MC type so that they are configured in aninitial state.

Always with reference to FIG. 4, each event-based micro-simulation 120step can comprise the following steps, performed by the simulationengine 10:

a step of initialisation of the event-based micro-simulation 130;

a first step of processing a radio resources management event 140 inwhich a traffic distribution of the voice type, realised by objects 19of the MS_MC type simulating the behaviour of the GSM mobile terminals,is analysed; and

a second step of processing a radio resources management event 150 inwhich a traffic distribution of the packet data type, realised byobjects 19 of the MS_MC type simulating the behaviour of the GPRS mobileterminals, is analysed.

More specifically, the step of initialising the event-basedmicro-simulation 130 can comprise the following steps, performed byobjects 17 of the BSC_MC type, objects 18 of the BTS_MC type and objects19 of the MS_MC type:

configuring the common channels, namely the channels that are used foractivation/deactivation of calls related to objects 19 of the MS_MCtype. In particular, module BSC_RRM_MC 20, included in object 17 of theBSC_MC type, configures the common channels for the cells controlled byeach object 18 of the BTS_MC type; for each cell and each channel,module BSC_RRM_MC 20 sets a value of transmitted power calculated basedon the configuration file 6; the minimum set of common configuredchannels comprises at least channel BCCH (“Broadcast Control CHannel)and channel CCCH (“Common Control CHannel”).

calculating one's own position by each object 19 of the MS_MC type that,for example, randomly extracts it within the area in which the GSM/GPRSnetwork will be planned;

calculating by module MS_RR_MC 24, included in each object of the MS_MCtype, the value of SAF (Service Activity Factor) parameter, for exampleby randomly extracting a value included between 0 and 1 for suchparameter. In particular, the SAF parameter represents the activityprobability associated with each GSM and GPRS mobile terminal for acertain simulated traffic distribution;

calculating by module MS_RR_MC 24, included in each object 19 of theMS_MC type simulating the behaviour of a GPRS mobile terminal, the TBC(Total Block Count) parameter, for example by randomly extracting avalue included between 0 and 1 for such parameter. In particular, theTBC parameter represents the amount of packet data traffic that eachGPRS mobile terminal can generate during the simulation;

managing the camping: each object 19 of the MS_MC type determines whichcommon BCCH channel receives with the higher signal level;

recording in module BSC_RR_MC 21, included in object 17 of the BSC_MCtype, all modules MS_RR_MC 24 included in each object 19 of the MS_MCtype whose calculated SAF value is, for example, lower than a threshold(SAF_THRESHOLD) read in the configuration file 6. The total number ofobjects 19 of the MS_MC type that take part in each step of event-basedmicro-simulation 120 can be calculated, in a known way, by using datacontained in the territory data base 7. Moreover, in the configurationfile 6 the total number of objects 19 of the MS_MC type is divided intoobjects 19 of the MS_MC type 19 simulating the behaviour of the GSMmobile terminals and objects 19 of the MS_MC type simulating thebehaviour of the GPRS mobile terminals. Module BSC_RR_MC 21 recordsmodules MS_RR_MC 24 by dividing them, according to what is establishedin the configuration file 6, into: modules MS_RR_MC 24 included inobjects 19 of the MS_MC type simulating the behaviour of the GSM mobileterminals and modules MS_RR_MC 24 included in objects 19 of the MS_MCtype simulating the behaviour of the GPRS mobile terminals;

sending to module BSC_RRM_MC 20, by module BSC_RR_MC 21, a request forradio resources related to each module MS_RR_MC 24 recorded by moduleBSC_RR_MC 21 (arrow 34 in FIG. 3);

sending by module BSC_RRM_MC 20 a message for assigning radio resourcesto each module MS_RR_MC 24 recorded by module BSC_RR_MC 21 (arrow 35 inFIG. 3); if there are no more radio resources available, moduleBSC_RRM_MC 20 sends a message for refusing the assignment of radioresources to the remaining modules MS_RR_MC 24;

sending by module BSC_RR_MC 21 a configuration message, for eachassignment message received in the previous step, to modules MS_RR_MC 24so that they use the radio resources assigned thereto by moduleBSC_RRM_MC 20 (arrow 36 in FIG. 3); in this way, module BSC_RR_MC 21performs the configuration of channels assigned to objects 19 of theMS_MC type simulating the behaviour of the GSM mobile terminals(dedicated-access channels, namely channels reserved to a single mobileterminal) and of channels assigned to objects 19 of the MS_MC typesimulating the behaviour of the GPRS mobile terminals (shared-accesschannels, namely channels used by one or more mobile terminals);

sending by module BSC_RR_MC 21 a configuration message of the startingpower to modules BTS_PHY_MC 23, associated with cells in which there areobjects 19 of the MS_MC type simulating the behaviour of the GSM mobileterminals, and to modules MS_RR_MC 24 included in such objects (arrows37 and 38 in FIG. 3).

Moreover, the first step of processing a radio resources managementevent 140 comprises at least a step of processing a power control event,performed by objects 19 of the MS_MC type simulating the behaviour ofthe GSM mobile terminals (defined herein below as “GSM-type objects”).During such step, the GSM-type objects transmit/receive ondedicated-access channels assigned thereto by module BCS_RRM_MC 20 and,simultaneously, through the respective modules MS_PHY_MC 25, performmeasures on such channels, for example of the RXLEV parameterrepresenting the level of received power and the RXQUAL parameterrepresenting the quality level of the received service. Correspondingly,modules BTS_PHY_MC 23 perform, on the same channels, the measures ofRXLEV and RXQUAL parameters received by them. These parameters areuseful to obtain, at the end of the step of processing the power controlevent, the update of its own transmission power by each GSM-type objectand each module BTS_PHY_MC 23.

In a preferred embodiment, the updated of its own transmission power byeach GSM-type object and each module BTS_PHY_MC 23 can provide for thecyclic repetition, for a number of times established in theconfiguration file 6, of the following steps:

sending to module BSC_RRM_MC 20 by modules MS_PHY_MC 25 a report messagecontaining the measured values of RXLEL and RXQUAL parameters (arrow 39in FIG. 3);

sending to module BSC_RRM_MC 20 by modules BTS_PHY_MC 23 a reportmessage containing the measured values of RXLEL and RXQUAL parameters(arrow 44 in FIG. 3);

processing by module BSC_RRM_MC 20 the measured values of RXLEL andRXQUAL parameters contained in the report message to calculate the newtransmission power of modules MS_PHY_MC 25 and modules BTS_PHY_MC 23;

sending by module BSC_RRM_MC 20 a configuration message of the newtransmission power value to modules MS_PHY_MC 25 (arrow 39 in FIG. 3);

sending by module BSC_RRM_MC 20 a configuration message of the newtransmission power value to modules BTS_PHY_MC 23 (arrow 44 in FIG. 3);

updating by modules MS_PHY_MC 25 their own transmission power dependingon the received configuration message of module BSC_RRM_MC 20; and

updating by modules BTS_PHY_MC 23 their own transmission power dependingon the received configuration message of module BSC_RRM_MC 20.

The second step of processing a radio resources management event 150provides for the simulation of a scheduling management algorithm ofobjects 19 of the MS_MC type simulating the behaviour of the GPRS mobileterminals (defined herein below as “GPRS-type objects”) on theshared-access channels of the GSM/GPRS network.

In a preferred embodiment of the present invention, the simulatedscheduling management algorithm uses a time division mode for managingthe scheduling. In this mode, time is divided into elementary units (forexample 20 ms long) called block periods: for each block period, thescheduling management algorithm assigns to at least one mobile terminalat least one shared-access channel: such mobile terminal is then enabledto transmit on such channel during such block period.

Specifically, the scheduling management algorithm is simulated throughmodule BSC_MAC_MC 22, included in object 17 of the BSC_MC type, thatduring the second step of processing a radio resources management event150, performs one or more scheduling events (each simulating one blockperiod) as will be better described in the following description.

More in detail, the second step of processing a radio resourcesmanagement event 150 starts when module BSC_RR_MC 21 sends to moduleBSC_MAC_MC 22 a configuration message (arrow 40 in FIG. 3) containing atleast the following elements:

number (NumRBslot) of scheduling events to be performed;

time length of each scheduling event, for example 20 ms (this parameteris contained in the configuration file 6); and

list of GPRS-type objects to which radio resources have been assigned intransmission/reception for the current step of event-basedmicro-simulation 120. This list is divided into one or more sub-lists,each one comprising the number of GPRS-type objects that, for thecurrent step of event-based micro-simulation 120, are assigned to eachshared-access channel included in the GSM/GPRS network; such list isdetermined depending on the assignment of radio resources performed bymodule BSC_RRM_MC 20 during each step of initialisation of theevent-based micro-simulation 130, by counting, for each shared-accesschannel how many GPRS-type objects received such channel as assignment;and

starting power to be assigned to modules BTS_PHY_MC 23 included in eachobject 18 of the BTS_MC type, associated with cells in which there areobjects 19 of the MS_MC type simulating the behaviour of the GPRS mobileterminals (arrow 41 in FIG. 3).

Module BSC_MAC_MC 22, through the simulation engine 10, performs theNumRBslot scheduling events provided in the configuration message sentby module BSC_RR_MC 21, with a timing that, for example, is 20 ms.During each scheduling event, module BSC_MAC_MC 22 performs thefollowing operations:

reviews (150 a) every GPRS-type object belonging to the list ofGPRS-type objects with radio resources assigned intransmission/reception for the current step of event-basedmicro-simulation 120 and, for each sub-list, and therefore for eachshared-access channel, selects the GPRS-type object occupying the firstplace of the related sub-list, keeping memory of the latest selectedGPRS-type object in the sub-list itself;

enables (150 b) to transmission/reception, on the respectiveshared-access channel, each GPRS-type object selected in the previousstep (arrows 42 and 43 in FIG. 3). Under this condition, each GPRS-typeobject can transmit/receive on at least one shared-access channelassigned thereto simultaneously performing measures about thesignal/noise ratio being present in that channel;

disables (150 c) each previously-enabled GPRS-type object, once thislatter one has performed the respective measures of signal/noise ratioon the shared-access channels assigned thereto;

removes (150 d) each previously-disabled GPRS-type object from the firstposition of the respective sub-list, inserting it at the bottom of thesub-list itself. In this way, the GPRS-type objects that will be enabledto transmission/reception in the scheduling event to be simulated arethose that in the just simulated scheduling event occupied the secondposition of the respective sub-list, and so on for all followingscheduling events to be simulated.

The operation proceeds similarly to what is described above for each oneof the NumRBslot scheduling events provided in the configuration messagesent by module BSC_RR_MC 21 to module BSC_MAC_MC 22 at the beginning ofthe second step of processing a radio resources management event 150.

At the end of each scheduling event, a step for collecting andprocessing 150 e all measures of signal/noise ratio performed by eachGPRS-type object, is also provided. During this step, the meansignal/noise ratio measured by each GPRS-type object is also calculated.All mean signal/noise ratios calculated in the step of collecting andprocessing 150 e are then stored in the simulation data base 8.

Now the simulation engine 10 verifies whether the module BSC_MAC_MC 22has performed all scheduling events provided in the configurationmessage sent by module BSC_RR_MC 21. If the check has a positive result,the simulation engine 10 ends the second step of processing a radioresources management event 150 and, in a preferred embodiment of thepresent invention, controls the execution of a step for calculating 160the mean throughput associated with each GPRS-type object. If instead,the check has a negative result, the simulation engine 10 controls theexecution of a new scheduling event.

In particular, the mean throughput is calculated depending on theformula:

$T_{MS} = {\sum\limits_{i = 1}^{N_{TS}}\frac{T_{{TS},i}*N_{{RB},{TX}}}{numRBslot}}$

where T_(TS,i) is the mean throughput related to the i-th shared-accesschannel assigned to the GPRS-type object (this value is calculated byusing curves, set in the configuration file 6, that, for eachshared-access channel assigned to the GPRS-type object during the stepof executing the event-based micro-simulation 140, link the values ofmean signal/noise ratio to the values of mean throughput); N_(RB,TX) isthe number of scheduling events in which the GPRS-type object has beenenabled to transmission/reception by module BSC_MAC_MC 22; numRBslot isthe number of scheduling events performed by module BSC_MAC_MC 22;N_(TS) is the number of shared-access channels assigned to the GPRS-typeobject during the second step of processing a radio resources managementevent 150. All values of mean throughput calculated during the step ofcalculating 160 are then stored in the simulation data base 8.

Now the simulation engine 10 verifies whether the simulation algorithm100 has performed all event-based micro-simulations steps 120 providedin the configuration file 6. If the check has a positive result, thesimulation engine 10 ends the simulation algorithm 100 (stop), otherwiseit controls the execution of a new event-based micro-simulation step120.

In FIG. 5 an operating example of module BSC_MAC_MC 22 is shown. Inparticular, in the example in FIG. 5 a first 200, a second 210 and athird 220 scheduling event are simulated in succession regarding fourGPRS-type objects (MS_MC1, MS_MC2, MS_MC3, MS_MC4) on a first 230, asecond 240 and a third 250 shared-access channel for the uplinkconnection (namely for the communication occurring from mobile terminalto transceiver station).

As shown in FIG. 5, the sub-list of GPRS-type objects (MS_MC1, MS_MC2)is assigned to the first shared-access channel 230; the sub-list ofGPRS-type objects (MS_MC1, MS_MC2, MS_MC4) is assigned to the secondshared-access channel 240; the sub-list of GPRS-type objects (MS_MC2,MS_MC3) is assigned to the third shared-access channel 250.

During the first scheduling event 200, module BSC_MAC_MC 22 selects oneach shared-access channel 230, 240, 250, the GPRS-type object thatoccupies the first position of the sub-list assigned to such channel,namely: the GPRS-type object (MS_MC1) is selected on the firstshared-access channel 230, the GPRS-type object (MS_MC4) is selected onthe second shared-access channel 240, the GPRS-type object (MS_MC3) isselected on the third shared-access channel 250.

After having selected the GPRS-type objects MS_MC1, MS_MC4, MS_MC3,occupying the first place of the respective sub-list, module BSC_MAC_MC22 enables them for receiving on the shared-access channel assignedthereto, namely: the GPRS-type object (MS_MC1) is enabled for receivingon the first shared-access channel 230, the GPRS-type object (MS_MC4) isenabled for receiving on the second shared-access channel 240, theGPRS-type object (MS_MC3) is enabled for receiving on the thirdshared-access channel 250.

After each GPRS-type object (MS_MC1, MS_MC4, MS_MC3) enabled forreceiving has performed the respective measures of signal/noise ratio,module BSC_MAC_MC 22 disables it and removes it from the first positionof the respective sub-list in order to insert it at the bottom of thesub-list itself. In this way, the following is obtained: the firstposition of the sub-list assigned to the first shared-access channel 230is now occupied by the GPRS-type object (MS_MC2) while the GPRS-typeobject (MS_MC1) is at the bottom of the sub-list; the first position ofthe sub-list assigned to the second shared-access channel 240 is alsooccupied by the GPRS-type object (MS_MC2), while object MS_MC4 is at thebottom of the sub-list; the first position of the sub-list assigned tothe third shared-access channel 250 is also occupied by the GPRS-typeobject (MS_MC2) while the GPRS-type object (MS_MC3) is at the bottom ofthe sub-list.

Now, module BSC_MAC_MC 22 performs the second scheduling event 210 inwhich it selects on each shared-access channel 230, 240, 250, theGPRS-type object that now occupies the first position of the sub-listassigned to such channel. In this case on all three shared-accesschannels 230, 240, 250, the GPRS-type object (MS_MC2) is selected.

After the GPRS-type object (MS_MC2) has been selected, module BSC_MAC_MC22 enables it for receiving on the shared-access channels 230, 240, 250and, after the GPRS-type object (MS_MC2) has performed the respectivemeasures of signal/noise ratio, module BSC_MAC_MC 22 disables it andremoves it from the first position of each sub-list in order to insertit at the bottom of the sub-list itself. In this way, the following isobtained: the first position of the sub-list assigned to the firstshared-access channel 230 is now occupied again by the GPRS-type object(MS_MC1) while the GPRS-type object (MS_MC2) is at the bottom of thesub-list; the first position of the sub-list assigned to the secondshared-access channel 240 is now occupied by the GPRS-type object(MS_MC1), while the GPRS-type object (MS_MC2) is at the bottom of thesub-list; the first position of the sub-list assigned to the thirdshared-access channel 250 is again occupied by the GPRS-type object(MS_MC3) while the GPRS-type object (MS_MC2) is at the bottom of thesub-list.

Now, module BSC_MAC_MC 22 performs the third scheduling event 220, inwhich it selects on each shared-access channel 230, 240, 250, theGPRS-type object that now occupies the first position of the sub-listassigned to such channel, namely: the GPRS-type object (MS_MC1) isselected on the first and on the second shared-access channel 230, 240,while the (MS_MC3)-type object is again selected on the thirdshared-access channel 250.

After having selected the GPRS-type objects MS_MC1, MS_MC3, occupyingthe first place of the respective sub-list, module BSC_MAC_MC 22 enablesthem for receiving on the shared-access channel assigned thereto,namely: the GPRS-type object (MS_MC1) is enabled for receiving on thefirst and the second shared-access channel 230, 240, while the(MS_MC3)-type object is again enabled for receiving on the thirdshared-access channel 250. Then, module BSC_MAC_MC 22 ends thescheduling events simulation.

Advantageously, the simulation method according to the invention allowsto simulate, with adequate accuracy and reliability, the schedulingmanagement procedures/algorithms used in mobile telephone networks withshared-access channels without taking into account the time variable andthereby minimising the required times for simulation.

It is finally clear that numerous modifications and variations, allfalling within the inventive concept, as defined by the enclosed claims,can be made to the simulation method and its related simulator, hereindescribed and shown.

The simulator 5 can for example be made using any type of computer(Intel, SUN, Apple, etc.) and operating system (Windows, Linux, Unix,MAC OS, etc.).

Moreover, the use of ANSI C++ programming language for implementing thesimulator 5 is only one possible choice; the simulator 5 can beimplemented also using other programming languages, such as for exampleJava, Delphi, Visual Basic, etc. The choice of the ANSI C++ languageshas been dictated by the good programming flexibility offered by saidprogramming language and by the high level of performance that can beobtained in the finished program in terms of execution speed.

Moreover, the simulator 5 according to the invention can be used alsofor simulating other types of mobile telephone networks in which thereare shared-access channels. In such case it is necessary to provide forthe insertion of a module similar to the third module BSC_MAC_MC 22 thathas been described previously, that takes care of managing thescheduling of mobile terminals, which generate a packet data traffic onthe shared-access channels. For example, it is possible to simulate theUMTS-FDD (Universal Mobile Telecommunications System—Frequency DivisionDuplex) mobile telephone network by taking into account the DSCH(Downlink Shared CHannel) channels, or the HS-DSCH (High Speed DownlinkShared CHannel) network, or also the EDGE (Enhanced Data rate for GlobalEvolution) network.

A further advantage of the simulator 5 is given by the chance of usingsome of the results provided by a simulator of the dynamic type orprovided by measures performed on the real network, in order tocalculate, for example, the number of GPRS-type objects to be simulated,according to the type of traffic that has to be taken into account.

As already previously mentioned, the simulator 5 can also be used forsimulating GPRS mobile terminals generating a data traffic that isdifferent from a data traffic of the FTP (File Transfer Protocol) type.For example, the simulator 5 can also be used for simulating GPRS mobileterminals generating a packet data traffic of the WWW (World Wide Web)type. In this case, the number of GPRS-type objects generating a packetdata traffic of the WWW type that can be simulated through the simulator5 can be computed by taking into account, for example, the followingfactors:

the characteristics of the traffic of the WWW type to be simulated, suchas for example the mean number of packets forming each WWW page to bedownloaded, the mean number of WWW pages forming an Internet session,the speed with which data are transmitted by the Web server from whichthe pages must be downloaded;

the mean downloading time of a single object of a WWW page in a networksimilar to the one that has to be simulated, obtained for example from asimulator of the dynamic type that has simulated this network or frommeasures performed on the real network;

the probability of allocating GPRS-type objects on shared-accesschannels not used by other GPRS-type objects.

Such probability value must be used for obtaining the mean number ofshared-access channels to be simulated, and is calculated by taking intoaccount the following factors:

parameters related to the shared-access channels assigning algorithm,such as for example: maximum number of GPRS-type objects that can beassigned for each shared-access channel, number of shared-accesschannels used by each GPRS-type object for packet data transmission;

characteristics of the WWW traffic to be taken into account, such as forexample: mean size of packets, mean size of WWW pages packet header,mean number of packets per WWW page;

mean downloading time of a single object of a WWW page in a networksimilar to the one that has to be simulated, obtained, for example, asdescribed previously, from measures performed on the real network orfrom a simulator of the dynamic type used for simulating the networkthat is similar to the network that has to be simulated; and

constants characterising the scenario to be simulated, such as, forexample, mean traffic per cell; such quantities are obtained, forexample, from a simulator of the dynamic type that has simulated anetwork similar to the one that has to be simulated or from measuresperformed on the real network.

1-11. (canceled)
 12. A method for simulating a mobile telephone networkwith shared-access channels comprising at least the steps of: simulatinga first configuration of said mobile telephone network; simulating asecond configuration of said mobile telephone network; said first andsecond configuration of said mobile telephone network beingstatistically independent one from the other; each one of said steps ofsimulating comprising at least the steps of: determining a number ofmobile terminals generating a packet data traffic; assigning to a listof mobile terminals in said number of mobile terminals generating apacket data traffic, at least one shared-access channel of said mobiletelephone network to be simulated; and performing a schedulingmanagement algorithm of said list of mobile terminals on saidshared-access channel.
 13. The method according to claim 12, whereinsaid step of performing a scheduling management algorithm comprises thestep of: enabling in succession the mobile terminals in said list ofmobile terminals for transmitting/receiving on said shared-accesschannel.
 14. The method according to claim 13, wherein said step ofenabling in succession the mobile terminals in said list of mobileterminals, comprises the steps of: selecting a first mobile terminal onsaid list of mobile terminals, said first mobile terminal occupying afirst position on said list of mobile terminals; enabling said firstmobile terminal for transmitting/receiving on said shared-accesschannel; moving said first mobile terminal from said first position onsaid list of mobile terminals to a last position on said list of mobileterminals; selecting a second mobile terminal on said list of mobileterminals, said second mobile terminal occupying said first position onsaid list of mobile terminals; enabling said second mobile terminal fortransmitting/receiving on said shared-access channel; moving said secondmobile terminal from said first position on said list of mobileterminals to a last position on said list of mobile terminals; andrepeating the previous steps for each mobile terminal on said list ofmobile terminals.
 15. The method according to claim 14, wherein saidsteps of moving said first and second mobile terminal from said firstposition on said list of mobile terminals comprises the step ofdisabling said first and second mobile terminal fromtransmitting/receiving on said shared-access channel.
 16. The methodaccording to claim 12, wherein said packet data traffic is of thecontinuous type.
 17. The method according to claim 12, wherein saidpacket data traffic is of the world wide web type.
 18. The methodaccording to claim 12, wherein said scheduling management algorithm isbased on a time division mode.
 19. The method according to claim 12,wherein each one of said steps of simulating a configuration of saidmobile telephone network further comprises the steps of: determining anumber of mobile terminals generating voice traffic; and processing atleast one radio resources management event related to the voice trafficdistribution associated with said number of mobile terminals.
 20. Themethod according to claim 19, wherein said radio resources managementevent is a power control event.
 21. A system for simulating at least afirst and a second configuration of a mobile telephone network, saidfirst and second configuration of said mobile telephone network beingstatistically independent one from the other and each comprising anumber of mobile terminals to be simulated generating a packet datatraffic, said simulating system comprising: at least one objectrepresenting a network controller belonging to said mobile telephonenetwork; said at least one object comprising modules configured for:assigning to a list of mobile terminals in said number of mobileterminals generating a packet data traffic, at least one shared-accesschannel of said mobile telephone network to be simulated; and performinga scheduling managing algorithm of said list of mobile terminals on saidshared-access channel.
 22. A program for an electronic processor that iscapable of being loaded in the memory of at least one electronicprocessor and comprising program codes capable of performing the stepsof the method according to claim 12, when said program is executed bysaid electronic processor.